The present invention relates to percutaneous angioscopy catheters, and more particularly to percutaneous angioscopy catheters which have multiple lumens.
Angioscopy is increasingly being used to observe the interior of blood vessels during a variety of procedures including, for example, lower extremity revascularization. The use of an angioscope allows the surgeon to immediately detect and correct technical errors and deficiencies, while the surgery is being performed. Angioscopy may also facilitate intraluminal therapeutic procedures, such as thrombectomy and embolectomy. Advances in fiberoptic technology and the availability of flexible angioscopes as small as a millimeter or less, allow access to most blood vessels of the body. However, despite these advances, the inability to see through blood because of the opaque nature of the blood and the resulting need for removal of blood from the visual field remain the primary obstances to the widespread and routine use of angioscopy during lower extremity revascularization and other procedures.
In percutaneous angioscopy, the angioscope is inserted through the skin and into a blood vessel by means of a catheter which has a bore or "lumen" through which the angioscope is passed. An angioscopy catheter typically requires additional channels or lumens through which a variety of procedures are performed, such as balloon inflation and deflation, irrigation, etc. More specifically, in percutaneous angioscopy, a fluid is typically delivered through a separate lumen to a balloon provided at the distal end of the lumen to inflate the balloon and thereby occlude the blood vessel and prevent the flow of blood. Often through yet another lumen. the blood vessel at the distal end of the catheter is irrigated with a liquid such as a saline solution to clear the viewing area adjacent the angioscope. Such multiple lumens often cause the catheter to have an undesirably large diameter. It is well known that the insertion of a large angioscopy catheter into a blood vessel can cause an irreversible spasm in the blood vessel or other serious damage to the interior wall of the vessel. Therefore, the diameter of an angioscope catheter should be kept as small as practical. On the other hand, if multiple lumens are provided within a catheter having a relatively small diameter, the efficiency of the lumens, particularly the irrigation and balloon inflation/deflation lumens, can be significantly impaired.
Further, a percutaneous catheter requires "pushability" to prevent a catheter from collapsing as the catheter is being inserted, as well as flexibility to maneuver through blood vessels which curve, convolute and angle. If the diameter of a catheter is made small, the percutaneous catheter may not have a sufficient rigidity to provide the desired pushability. On the other hand, increasing the diameter of the catheter to increase rigidity is limited by other considerations, including minimizing damage to the blood vessel as noted above.